The MicroTCA is a platform specification formulated by the peripheral component interconnect (PCI) industrial computer manufacturers group (PICMG). The MicroTCA adopts advanced mezzanine cards (AMCs) to construct a modular communication platform with a small capacity and a low cost, which is mainly applied to small-scale telecom equipment or enterprise-level communication equipment such as a central office. Currently, the standard specification version is PICMG MicroTCA.0 R1.0.
The MicroTCA may be set to various product forms. According to requirements of different services, a MicroTCA system may be configured with different MicroTCA Carrier Hubs (MCHs) and different amount of AMCs with different sizes. The MicroTCA system is applicable to a cabinet with a depth of 300 mm, and is also suitable for being placed in a cabinet with a depth of 600 mm in a back-to-back installation manner.
As shown in FIG. 1, main functional modules of a MicroTCA system include: a chassis, power modules (PMs), MCHs, and AMCs. A backplane in the chassis is connected to the MCHs, the AMCs, and the PMs. The MCHs, the AMCs, and the PMs are connected and exchange data with one another via circuits in the backplane. The MCH is a central module of the MicroTCA system, and provides management, exchanging, clock, and test functions for the MicroTCA system.
In addition, the MicroTCA system further includes a joint test action group (JTAG) testing unit. The JTAG is an international standard test protocol, and is mainly applied to interconnection tests in the MicroTCA system, for example, a data connection failure test between cards, or an interconnection failure between chips. The JTAG is capable of testing data connection and clock connection in the MicroTCA system. The JTAG testing unit set in the MicroTCA system provides a testing port connected to a to-be-tested unit in the system. A main element of the JTAG testing unit is a JTAG switch module (JSM) Generally, the JTAG testing unit is realized by plugging a JSM into a JTAG slot, and the JTAG slot provides a JTAG testing unit connector. The JTAG testing unit connector is provided with connecting ports connected to the to-be-tested unit and the JTAG control unit, and a connecting port connected to a load power. The connection relationships are shown in FIG. 2. The connections among the JSM, the JTAG control unit, and the to-be-tested units adopt a star topology structure, in which the JTAG control unit may be set in the MCH, and may also be realized by an external test tool; and the to-be-tested units are generally AMCs.
FIG. 3 is a functional block diagram of a JSM. As shown in FIG. 3, the JSM mainly includes a primary switch module, a port switch module, and a power supply module. The primary switch module is configured to be connected to the connecting port on the JTAG testing unit connector for being connected to the JTAG control unit, and connected to the MCHs or an external test tool. The port switch module is configured to be connected to the connecting port on the JTAG testing unit connector for being connected to the to-be-tested units, and connected to the AMCs. The power supply module is configured to be connected to the connecting port on the JTAG testing unit connector for supplying the load power, to supply a load power for the JTAG testing unit. Ports connected to the AMCs include: a test data output (TDO) port, configured to output data of the JSM to the AMCs; a test data input (TDI) port, configured to input the AMC data into the JSM; a test clock input (TCK) port, configured to input a test clock; a test mode select (TMS) port, configured to set a JTAG port in a certain specific test mode; and a test reset (TRST) port, configured to reset the test, which is activated under a low level. The connection of the MCHs and JSM has already been defined in the MicroTCA.0R1.0.
During the implementation of the present invention, the inventor finds that the prior art at least has the following problems.
In the prior art, generally, a JTAG slot is additionally disposed on a backplane, and occupies exclusive backplane space. However, the JTAG slot is merely provided for the JSM to be plugged therein for testing the product in the production process before the MicroTCA system leaves the factory, and then the JTAG slot is in an idle state after the MicroTCA system leaves the factory. Furthermore, slots for other units of the MicroTCA system need to be provided on the backplane of the MicroTCA system, and the backplane space is rather limited. In addition, the additionally set JTAG slot occupies exclusive backplane space, which apparently causes waste of the backplane space.